FDNY Written Exam Questions and Answers with 100% Correct Answers
Already Graded A+
A more efficient centrifugal compressor operation results from - (ANSWER)Lowering the condensing
pressure
The heat removed from the refrigerant in a condenser is - (ANSWER)Sensible and latent heat
According to the New York City fire code, refrigerant containers must - (ANSWER)Be approved by the US
Department of Transportation
The cylinder unloader works by - (ANSWER)Keeping the suction valve opened while the compressor is in
the return stroke
In most semi-hermetic compressors, the suction vapor is used to - (ANSWER)Cool the motor
The amount of refrigerant that flows through the orifices of an economizer is determined by the -
(ANSWER)Difference between the high side and low side pressure
The installation of an inline refrigerant cleaning system is advisable to - (ANSWER)Remove impurities
from the system
The type of refrigerant system least likely to leak refrigerant into the building space is - (ANSWER)The
indirect system
The compression ratio for a reciprocating compressor with a suction pressure of 65 PSIG and a discharge
pressure of 120 PSIG is closest to - (ANSWER)1.69
A superheated vapor is - (ANSWER)Dry vapor above the saturation temperature
A condenser water pump cavitating is most likely caused by - (ANSWER)A faulty cooling tower water
level controller
,FDNY Written Exam Questions and Answers with 100% Correct Answers
Already Graded A+
A centrifugal water pump is known as a lift pump when - (ANSWER)The water supply to the pump
suction inlet is below the pump level
A TXV is used to maintain constant - (ANSWER)Evaporator superheat
A chilled water supply of 55°F for human comfort is - (ANSWER)Too high for human comfort purpose
The packing gland of a centrifugal pump serves to - (ANSWER)Keep air out of the pumps when the
impeller housing is under negative pressure
Capacity control of a reciprocating hermetic compressor is typically achieved through -
(ANSWER)Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that - (ANSWER)A
pure liquid refrigerant will enter the metering device
If a compressor discharge temperature has dropped significantly and the suction line pressure is high,
this may be caused by - (ANSWER)An expansion valve that is open too wide
A low side float valve is used to maintain - (ANSWER)The level of the refrigerant in the evaporator
The ASHRAE refrigerant safety classification indicating no flammability and lower toxicity is -
(ANSWER)A1
When an expansion valve is operating properly, the end of the evaporator will contain - (ANSWER)Only
superheated vapor
, FDNY Written Exam Questions and Answers with 100% Correct Answers
Already Graded A+
Information not contained in a Material Safety Data Sheet (MSDS) includes - (ANSWER)Cost of the
material
In a steam turbine, the Kingsbury thrust bearing functions to - (ANSWER)Maintain axial positioning of
the rotor shaft
A centrifugal water pump is considered fully primed when - (ANSWER)The pump is full of liquid
To avoid collapsing tubing when making bends, a refrigerant engineer should use - (ANSWER)Lever type
tubing bender
A reciprocating compressor making a clicking sound during operation, if not caused by worn parts, is
probably due to - (ANSWER)Slugging of the liquid refrigerant
For a refrigerant to become superheated, it must be heated in a section of the low side refrigerant line -
(ANSWER)Where no liquid refrigerant is present
After all liquid refrigerant has been recovered, the system - (ANSWER)Should not be opened until all
vapor has been recovered
The removal rate of refrigerant using a portable compressor recovery unit gradually slows down because
- (ANSWER)The vapor density is decreasing
If the water level in all cooling tower cells is very low, the immediate action should be to - (ANSWER)Add
additional makeup water to the cooling tower
The height of the water column, in feet, with a pressure gauge reading 140 PSIG is closest to -
(ANSWER)323 feet
The device that protects a steam turbine from excessive speed is the - (ANSWER)Governor assembly
Already Graded A+
A more efficient centrifugal compressor operation results from - (ANSWER)Lowering the condensing
pressure
The heat removed from the refrigerant in a condenser is - (ANSWER)Sensible and latent heat
According to the New York City fire code, refrigerant containers must - (ANSWER)Be approved by the US
Department of Transportation
The cylinder unloader works by - (ANSWER)Keeping the suction valve opened while the compressor is in
the return stroke
In most semi-hermetic compressors, the suction vapor is used to - (ANSWER)Cool the motor
The amount of refrigerant that flows through the orifices of an economizer is determined by the -
(ANSWER)Difference between the high side and low side pressure
The installation of an inline refrigerant cleaning system is advisable to - (ANSWER)Remove impurities
from the system
The type of refrigerant system least likely to leak refrigerant into the building space is - (ANSWER)The
indirect system
The compression ratio for a reciprocating compressor with a suction pressure of 65 PSIG and a discharge
pressure of 120 PSIG is closest to - (ANSWER)1.69
A superheated vapor is - (ANSWER)Dry vapor above the saturation temperature
A condenser water pump cavitating is most likely caused by - (ANSWER)A faulty cooling tower water
level controller
,FDNY Written Exam Questions and Answers with 100% Correct Answers
Already Graded A+
A centrifugal water pump is known as a lift pump when - (ANSWER)The water supply to the pump
suction inlet is below the pump level
A TXV is used to maintain constant - (ANSWER)Evaporator superheat
A chilled water supply of 55°F for human comfort is - (ANSWER)Too high for human comfort purpose
The packing gland of a centrifugal pump serves to - (ANSWER)Keep air out of the pumps when the
impeller housing is under negative pressure
Capacity control of a reciprocating hermetic compressor is typically achieved through -
(ANSWER)Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that - (ANSWER)A
pure liquid refrigerant will enter the metering device
If a compressor discharge temperature has dropped significantly and the suction line pressure is high,
this may be caused by - (ANSWER)An expansion valve that is open too wide
A low side float valve is used to maintain - (ANSWER)The level of the refrigerant in the evaporator
The ASHRAE refrigerant safety classification indicating no flammability and lower toxicity is -
(ANSWER)A1
When an expansion valve is operating properly, the end of the evaporator will contain - (ANSWER)Only
superheated vapor
, FDNY Written Exam Questions and Answers with 100% Correct Answers
Already Graded A+
Information not contained in a Material Safety Data Sheet (MSDS) includes - (ANSWER)Cost of the
material
In a steam turbine, the Kingsbury thrust bearing functions to - (ANSWER)Maintain axial positioning of
the rotor shaft
A centrifugal water pump is considered fully primed when - (ANSWER)The pump is full of liquid
To avoid collapsing tubing when making bends, a refrigerant engineer should use - (ANSWER)Lever type
tubing bender
A reciprocating compressor making a clicking sound during operation, if not caused by worn parts, is
probably due to - (ANSWER)Slugging of the liquid refrigerant
For a refrigerant to become superheated, it must be heated in a section of the low side refrigerant line -
(ANSWER)Where no liquid refrigerant is present
After all liquid refrigerant has been recovered, the system - (ANSWER)Should not be opened until all
vapor has been recovered
The removal rate of refrigerant using a portable compressor recovery unit gradually slows down because
- (ANSWER)The vapor density is decreasing
If the water level in all cooling tower cells is very low, the immediate action should be to - (ANSWER)Add
additional makeup water to the cooling tower
The height of the water column, in feet, with a pressure gauge reading 140 PSIG is closest to -
(ANSWER)323 feet
The device that protects a steam turbine from excessive speed is the - (ANSWER)Governor assembly
